The present invention relates to driver actuated devices for preventing theft of unoccupied automobiles. More particularly, the present invention relates to circuits which can be readily provided in the electrical system of a conventional automobile so that when armed the unathorized opening of any one of the passenger doors, trunk lid, hood, or fuel door will result in intermittent blasting of the automobile horn, together with flashing of the directional and brake lamps.
As a result of the continuing increase in the crime rate much attention has been focused upon various driver-armed systems for preventing theft of unoccupied automobiles. Many of these systems include complex components which make their installation both costly and time consuming. Others are easily disarmed by the experienced car thief. Often such systems are triggered by component failures or by external forces acting on the car which are not the result of an attempted car theft. This frequently results in annoying siren noise to neighbors, and all too frequently, run down car batterys. For example, many presently available systems include tilt switches which may be inadvertently closed by a ball bouncing off the car, or by heavy wind or rain.
Recently at least one CADILLAC automobile has been available with a theft deterrent option. When armed, if a person reaches in from outside the car and unlocks the door, the car horn will blast intermittently and the headlights will flash on and off. A starter-disablement circuit thereafter prevents the car engine from being started by putting the key in the ignition. The theft-deterrent system can be shut off by placing the key in the door lock. Details of the exact circuitry of this system are not presently known to me.
In my U.S. Pat. Nos. 3,263,211; 3,372,373; and 3,372,374, I have disclosed various flashing hazard light circuits which are adapted to be incorporated into the electrical systems of existing automobiles with readily available components. Also of general interest in the automobile wiring field are U.S. Pat. Nos. 2,321,803; 2,519,758; 2,654,079; 2,667,603; 2,761,121; 2,766,343; 2,802,142; 2,812,396; 2,844,810; 3,074,049; 3,182,289; and 3,185,961.